Brett D. Gartrell

The prevalence of beak and feather disease virus infection in wild populations of parrots and cockatoos in New Zealand

Abstract The prevalence of beak and feather disease virus infection in wild populations of parrots and cockatoos in New Zealand METHODS: Eastern rosellas (Platycercus eximius, n=162) were caught from Te Puke, Wellington and Dunedin, using mistnets, between April 2004 and February 2006, and sulphurcrested cockatoos (Cacatua galerita, n=255) were captured for pet-trading from November 2001 to September 2004. Feathers from both species were tested for BFDV, using an established polymerase chain reaction (PCR) test. Post-mortem examinations were conducted on some of the eastern rosellas, and selected tissues from 24 birds positive for BFDV were examined using routine histological methods for the presence of characteristic inclusion bodies. RESULTS: Of the eastern rosellas, 24/162 (14.8%) were positive for BFDV, and the 95% confidence interval (CI) for true prevalence was estimated as 8.6–20.4%, which varied between regions. Eastern rosellas that were positive for BFDV showed no clinical or histological signs of disease or inclusion bodies. Of the sulphur-crested cockatoos, 70/255 (28%) were positive for BFDV, and the 95% CI for true prevalence was calculated as 22–33%. CONCLUSIONS: The surprisingly high prevalence of BFDV in wild eastern rosellas and sulphur-crested cockatoos has serious implications for the conservation of native parrots and the export of wild-trapped parrots and cockatoos from New Zealand. Serological studies for BFDV in wild exotic parrots, and molecular studies of virus genotype, are recommended to further characterise the origin and epidemiology of the disease in populations of wild exotic parrots and cockatoos in New Zealand.

The Nutritional, Morphologic, and Physiologic Bases of Nectarivory in Australian Birds

Abstract Nectarivorous birds are those that rely predominantly on the products of flowering trees and shrubs for food. Australian avian nectarivores include honeyeaters of the family Meliphagidae and lorikeets and swift parrots (Lathamus discolor) of the family Psittacidae. Nectar is a sugar-rich, liquid food source that provides abundant amounts of energy for birds that are able to harvest it. However, it contains very low levels of amino acids, vitamins, and trace minerals necessary for avian maintenance, growth, and reproduction. Therefore, birds classified as nectarivores need to forage for other food resources. Manna, honeydew, and lerp are common food sources for a variety of honeyeaters and nectarivorous parrots; these foods are high in carbohydrates and low in protein, similar to nectar. Pollen protoplasm is composed of highly digestible protein and contains a diverse amino acid profile; however, only 3 Australian species of psittacine birds have been recorded engaging in active pollen harvesting. Insects are thought to be the main source of protein for nectarivores. Nectarivorous birds have developed a variety of morphologic and physiologic adaptations. Morphologic adaptations to nectarivory include changes in body size, plumage, beak and tongue structure, and the alimentary organs. The physiology of nectarivory is still poorly understood, but there are indications that adaptations may include lowered metabolic rates, lowered protein requirements, and changes in digestive and renal physiology. Considerable work is needed to illuminate the specific nutritional requirements of nectarivores for maintenance, growth, and reproduction.

Pharmacokinetics of butorphanol in broiler chickens

Butorphanol tartrate (2 mg/kg) was injected intravenously in 18 healthy broiler chickens to study its pharmacokinetics. Plasma samples were analysed by a highly sensitive high-performance liquid chromatography with diode-array detection method and pharmacokinetic parameters were calculated from the mean pooled data. With non-compartmental analysis, the terminal half-life (T1/2.z) was 71.3 minutes, clearance was 67.6 ml/minute/kg and the apparent volume of distribution was 6.9 l/kg. The concentration-time curve was also fitted to a two-compartmental model. In this analysis, elimination half-life (T1/2β) was 69.3 minutes, clearance was 74.6 ml/minute/kg and volume of distribution at steady state was 5.6 l/kg. The micro rate constants k21, k12 and k10 were 0.034, 0.050 and 0.029, respectively. Butorphanol was well distributed in the chickens with rapid clearance. It remained above the minimum effective concentration for analgesia in mammals for approximately two hours in the chickens.

Prevalence of Salmonella spp., and serovars isolated from captive exotic reptiles in New Zealand

Abstract AIM: To investigate the prevalence of Salmonella spp. in captive exotic reptile species in New Zealand, and identify the serovars isolated from this population. METHODS: Cloacal swabs were obtained from 378 captive exotic reptiles, representing 24 species, residing in 25 collections throughout New Zealand between 2008 and 2009. Samples were cultured for Salmonella spp., and suspected colonies were serotyped by the Institute of Environmental Science and Research (ESR). RESULTS: Forty-three of the 378 (11.4%) reptiles sampled tested positive for Salmonella spp., with 95% CI for the estimated true prevalence being 12–25% in exotic reptiles in this study population. Lizards tested positive for Salmonella spp. more often than chelonians. Agamid lizards tested positive more often than any other family group, with 95% CI for the estimated true prevalence being 56–100%.. Six Salmonella serovars from subspecies I and two from subspecies II were isolated. The serovar most commonly isolated was S. Onderstepoort (30.2%), followed by S. Thompson (20.9%), S. Potsdam (14%), S. Wangata (14%), S. Infantis (11.6%) and S. Eastbourne (2.3%). All of the subspecies I serovars have been previously reported in both reptiles and humans in New Zealand, and include serovars previously associated with disease in humans. CONCLUSIONS AND CLINICAL RELEVANCE: This study showed that Salmonella spp. were commonly carried by exotic reptiles in the study population in New Zealand. Several serovars of Salmonella spp. with known pathogenicity to humans were isolated, including S. Infantis, which is one of the most common serovars isolated from both humans and non-human sources in New Zealand. The limitations of this study included the bias engendered by the need for voluntary involvement in the study, and the non-random sampling design. Based on the serovars identified in this and previous studies, it is recommended native and exotic reptiles be segregated within collections, especially when native reptiles may be used for biodiversity restoration. Veterinarians and reptile keepers are advised to follow hygiene protocols developed to minimise reptile-associated salmonellosis.

Death by chocolate: A fatal problem for an inquisitive wild parrot

Abstract CASE HISTORY: An adult male kea (Nestor notabilis) in good body condition was found dead at Aoraki/Mt Cook Village, in the Southern Alps of New Zealand. The bird had previously been involved in behavioural tests of problem-solving ability. CLINICAL AND PATHOLOGICAL FINDINGS: The bird had substantial subcutaneous and abdominal reserves of fat. The crop contained 20 g of what appeared to be dark chocolate; a conservative estimate of the dose of methylxanthines ingested by the bird was 250 mg/kg theobromine, 20 mg/kg caffeine and 3 mg/kg theophylline. Histopathological examination revealed acute degenerative changes to hepatocytes, renal tubules, and cerebrocortical neurons. DIAGNOSIS: Acute combination methylxanthine toxicity after opportunistic ingestion of pchocolate. CLINICAL RELEVANCE: This is the first report of the pathological findings of methylxanthine toxicity in a wild parrot, and illustrates the need to ensure that kea are protected from the toxic by-products of human habitation, and the difficulties in ensuring this against a neophilic, inquisitive and innovative parrot.

Morphological Adaptations to Nectarivory of the Alimentary Tract of the Swift Parrot Lathamus discolor

Summary The morphology and microscopic architecture of the alimentary tract of the Swift Parrot was compared to that of the Green Rosella and Musk Lorikeet. Gut contents were evaluated grossly and by light microscopic examination. There were significant differences between the Swift Parrot and the Green Rosella in the scaled measurements of the length of the distal oesophagus and proventriculus and in the width of the crop, duodenum, intestine and cloaca. There were significant differences in the scaled measurements of the length of the gizzard and the width of the oesophagus, gizzard and duodenum between the Swift Parrot and the Musk Lorikeet. The results support previous findings that the Swift Parrot has retained some of the alimentary features of its granivorous ancestors. However, our findings suggest that the Swift Parrot may have adapted to nectarivory, not only with the development of a brush tongue, but also in changes to the crop, proventriculus and duodenum. The larger, more muscular gizzard and longer intestine may allow the Swift Parrot to use a diversity of dietary items when nectar and pollen are not readily available.

Evaluation of the pathogenicity of avipoxvirus strains isolated from wild birds in New Zealand and the efficacy of a fowlpox vaccine in passerines

Avipoxvirus (APV) infection is a highly contagious disease of birds and has been reported in more than 200 bird species, affecting both domesticated and free-ranging birds around the world. In New Zealand, at least three different strains of Avipoxvirus (APV) have been identified in a range of bird species.The pathogenicityof two APV strains isolated from wild birds in New Zealand, representing subclade A1 and subclade B1 were compared in zebra finches (Taeniopygia guttata). The efficacy of fowlpox vaccine at preventing clinical disease in passerines was also evaluated. Twenty-five zebra finches were divided into five groups (I-IV and a control group). Birds from Groups II and IV were vaccinated using fowl poxvirus vaccine prior to challenge. Subsequently two groups (I and II) were inoculated with a silvereye isolate (A1) and the other two groups (Group III and IV) were inoculated with a blackbird isolate (B1). Both inocula were previously propagated in chicken fibroblast cell culture. Birds in the control group were inoculated with sterile PBS. Skin thickness at the inoculation sites was measured and the development of additional skin lesions was monitored. Antibody development was measured by ELISA pre- and post virus inoculation. Both APV strains caused either swelling or hyperplasia at the inoculation site of non-vaccinated birds (4/5 in Group I and 5/5 in Group III). The swelling was milder and no foot lesions were observed in vaccinated birds before or after challenge with the silvereye or blackbird APV strains. These findings indicated that the fowlpox vaccine provided safe and appropriate protection for zebra finches exposed to the two wild APV strains and suggest that the vaccine has the potential to be used where APV threatens the captive management or translocation of endangered passerines.

Prevalence of Leucocytozoon spp, in the endangered yellow-eyed penguin Megadyptes antipodes

Yellow-eyed penguins on Stewart Island were identified with a Leucocytozoon spp. of a novel lineage in association with a high regional incidence of chick mortality (n=32, 100% mortality) during the November 2006 to January 2007 breeding season. Fourteen chicks from Stewart Island were examined post-mortem and histologically for Leucocytozoon infection. In addition, a survey of blood to detect Leucocytozoon spp. infections using PCR was performed on 107 yellow-eyed penguins from 4 distinct nesting areas on the South Island (Oamaru, Otago Peninsula, and Catlins) (n=95), and Stewart Island (n=12). The results of the study revealed that 2 of the 14 (14%) chicks necropsied showed severe, disseminated megaloschizont formation in the liver, spleen, lung, kidney and other tissues characteristic of leucocytozoonosis. Eighty-three percent (83%) of blood samples collected from Stewart Island penguins contained Leucocytozoon DNA, whereas samples from the 3 other nesting areas were negative for the blood parasite. Leucocytozoon spp. DNA sequences isolated from blood and tissues of adults (n=10) and chicks (n=7) were similar and grouped with other published Leucocytozoon spp. sequences but in a distinct cluster together with closely related isolates from a Western march harrier (Circus aerginosus) and common loon (Gavia immer). These findings suggest that yellow-eyed penguins on Stewart Island are infected with a regionally isolated, host-specific Leucocytozoon spp. which may contribute to the high chick mortality observed during this period.

COELOMIC IMPLANTATION OF SATELLITE TRANSMITTERS IN THE BAR-TAILED GODWIT (LIMOSA LAPPONICA) AND THE BRISTLE-THIGHED CURLEW (NUMENIUS TAHITIENSIS) USING PROPOFOL, BUPIVACAINE, AND LIDOCAINE

Abstract Intravenous propofol was used as a general anesthetic with a 2∶1 (mg∶mg) adjunctive mixture of lidocaine and bupivacaine as local anesthetics infiltrated into the surgical sites for implantation of satellite transmitters into the right abdominal air sac of 39 female and 4 male bar-tailed godwits (Limosa lapponica baueri and Limosa lapponica menzbeiri) and 11 female and 12 male bristle-thighed curlews (Numenius tahitiensis). The birds were captured on nesting grounds in Alaska, USA, and on overwintering areas in New Zealand and Australia from 2005 through 2008. As it was developed, the mass of the transmitter used changed yearly from a low of 22.4 ± 0.2 g to a high of 27.1 ± 0.2 g and weighed 25.1 ± 0.2 g in the final year. The mean load ratios ranged from 5.2% to 7.7% for godwits and from 5.7% to 7.5% for curlews and exceeded 5% for all years, locations, and genders of both species. The maximum load ratio was 8.3% for a female bar-tailed godwit implanted in Australia in 2008. Three godwits and no curlews died during surgery. Most birds were hyperthermic upon induction but improved during surgery. Two godwits (one in New Zealand and one in Australia) could not stand upon release, likely due to capture myopathy. These birds failed to respond to treatment and were euthanized. The implanted transmitters were used to follow godwits through their southern and northern migrations, and curlews were followed on their southern migration.

The prevalence of psittacine beak and feather disease virus infection in native parrots in New Zealand

Abstract AIM: To determine the prevalence of psittacine beak and feather disease virus (BFDV) infection in native parrots in New Zealand. METHODS: One hundred and sixty-nine wild native parrots and 143 captive native parrots throughout New Zealand were examined for the presence of BFDV, from June 2003 to January 2005. Feathers of each bird, and blood samples from 15 birds, were collected and submitted for PCR assay to detect BFDV. RESULTS: All of the samples from wild native parrots were negative for BFDV by PCR assays. Similarly, of the 143 PCR tests from captive native parrots 139 (97%) were negative for BFDV. However, a pair of red-crowned parakeets and two Antipodes Island parakeets from different captive facilities were found to be infected with BFDV. The infected birds showed no clinical signs suggestive of psittacine beak and feather disease (PBFD), although the second Antipodes Island parakeet was found dead, and had pathological changes consistent with acute septicaemia. CONCLUSIONS: The results indicate a very low prevalence of BFDV among free-living native parrots although captive birds, in particular native parakeets, are susceptible to BFDV infection, and the Antipodes Island parakeets may be susceptible to PBFD.